Leukocyte, extravasation

Middleton J, Patterson AM, Gardner L, Schmutz C, Ashton BA. Leukocyte extravasation chemokine transport and presentation by the endothelium. Blood 2002 100 3853-60. 

Nevertheless, there is also accumulating evidence that a certain regionalization exists in the mucosal immune system, in particular a dichotomy between the gut and the upper respiratory tract. Differences in the antigenic repertoire, adhesion molecules or chemokines involved in leukocyte extravasation might explain this disparity. Primed immune cells may tend to home to the effector sites corresponding to the inductive sites, where the initial antigen contact took place. Such regionalization within the common mucosal immune system has to be taken into account in the development of certain mucosal vaccines [11]. 

Leukocyte extravasation (movement of leukocytes out of the circulatory system)... 

The importance of TNF-a is noted in the activation of the endothelium. TNF-a induces endothelial cells to present E-selectin and intercellular adhesion molecule 1 (ICAM-1), both of which are ceU-adhesion molecules that mediate the mechanism of leukocyte extravasation, termed diapedesis (see Chapter 14). While this process is essential for the recruitment... 

Glycosyltransferases assemble polysaccharides from their monomeric units by adding activated nucleotide sugars to the growing carbohydrate chain [19]. The chemistry of glycosyltransferases is well known [20-22] and is illustrated in the biosynthesis of sialyl Lewis [23], an essential contributor to the cell adhesion process. In fact, without both the siahc acid and fucose components, the sialyl Lewis remnant is incapable of binding to selectins and effecting cell adhesion necessary for leukocyte extravasation [24-29]. 

Glycopeptides serve as target structures in the investigation of a variety of other biological events. For example, peptides presenting sialyl Lewis x (sLe ) may act as inhibitors of excessive leukocyte extravasation in the inflammatory response [193]. 

Tran EH, Hoekstra K, Van Rooijen N, Dijkstra CD, Owens T (1998) Immune invasion of the central nervous system parenchyma and experimental allergic encephalomyelitis, but not leukocyte extravasation from blood, are prevented in macrophage-depleted mice. J Immunol 161 3767... 

Antithrombin has been shown to promote the release of prostacyclin from endothelial cells [74] and to attenuate ischemia-induced leukocyte extravasation [75]. In addition, chemotactic effects of AT on neutrophils and signaling via interaction with cell-surface heparan sulfate proteoglycans... 

Selectins in Leukocyte Extravasation Function of a Common Epitope on L- and E-Selectin Mark A. Jutila... 

In the first adhesion step of the leukocytes extravasation process, selectins (including L-selectin, E-selectin, and P-selectin), along with heparan sulfate PGs,... 

Futher evidence for the importance of adhesion molecules as targets for antiinflammatory polysaccharides was provided by Dong and Murphy [74, 75]. They showed, using an in vivo mouse model that a glucuronoxylomannan from Cryptococcus neoformans inhibits leukocyte extravasation into sites of acute inflammation. They propose that binding to CD 18 (part of the cell adhesion molecule Mad) on human neutrophils is responsible for the observed inhibition of leukocyte migration. 

Mice lacking al,3Fuc-TVII are deficient in leukocyte extravasation into areas of inflammation, a phenotype similar to P- and E- selectin deficient mice and to LADII pathology in humans [101]. Unlike neutrophils, carcinoma cells may not express leukocyte cell surface glycoproteins (e.g. PSGL-1), however selectin ligands... 

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